The present invention relates generally to a method for manufacturing electroluminescent lamps for electronic devices and, more particularly, to an improved method for manufacturing and construction of electroluminescent lamps for an electronic device such as an electronic timepiece.
It is well known in the art that electroluminescent (xe2x80x9cELxe2x80x9d) lamps are generally included within the construction of dials and displays for electronic devices. The EL lamps permit an illumination of the dials and displays so that information exhibited thereon may be more readily viewed in an environment of low ambient light. EL lamps are generally constructed as layered structures. For example, U.S. Pat. No. 5,620,348, issued on Apr. 15, 1997, to Santana et al. describes an EL lamp comprising a transparent substrate, a front electrode, an EL layer, an insulating layer and a back electrode. The disclosure of U.S. Pat. No. 5,620,348, is incorporated by reference as if fully set forth herein.
Generally speaking, the substrate and the front electrode of the EL lamp are transparent to permit light emitted by an energized EL layer to pass through these layers to illuminate the dial or display configured on a face of the EL lamp. As is known, the EL layer is energized by application of an electrical potential between the front and back electrodes.
A perceived deficiency in these prior art EL lamps is the limitations in surface configurations for the face of the dials and displays. That is, the visual appearance of surface configurations and finishes of dials and displays incorporating conventional EL lamps generally are secondary to the need for transparency during illumination operations. In particular, conventional surface configurations for dials and displays do not provide for metallic finishes and/or coarse or smooth textured surfaces.
Therefore, the present invention provides a method for manufacturing and a construction of EL lamps that permits visually appealing surface configurations without sacrificing the transmission of light from energized EL layers to illuminate the dial and/or display.
Therefore, it is a first object and advantage of this invention to provide a method for manufacturing EL lamps having visually appealing surface configurations.
It is another object and advantage of this invention to provide a method for manufacturing and construction of EL lamps having a face with a surface configuration having a metallic and/or textured finish.
It is yet another object and advantage of the present invention to provide a material on the surface of the dial that can reflect incident ambient light and yet transmit light received from the EL layer when the EL layer is energized.
Further objects and advantages of this invention will become more apparent from a consideration of the drawings and ensuing description.
The foregoing and other problems are overcome and the objects and advantages are realized by an apparatus constructed in accordance with embodiments of this invention, wherein an improved method for manufacturing and construction of an EL lamp having a face with a surface configuration of a metallic and/or textured finish is disclosed.
Generally speaking, the present invention comprises an EL lamp for an electronic device that includes a transparent substrate having a first and a second surface, a translucent layer formed on the first surface and a transparent electrically conductive layer formed on the second surface of the transparent substrate. The EL lamp further includes an EL layer formed on the transparent conductive layer, an insulating layer formed on the EL layer, and an electrically conductive layer formed on the insulating layer. The translucent layer, the transparent substrate, the transparent electrically conductive layer, the EL layer, the insulating layer and the electrically conductive layer together comprise a layered assembly. In accordance with the present invention, the translucent layer includes a surface having a selected surface configuration.
In one embodiment, the selected surface configuration of the translucent layer includes a metallic finish. In another embodiment, the selected surface configuration includes either a coarse or a smooth, textured finish.
A method of manufacturing the EL lamp is also disclosed. The EL lamp is a layered assembly, which includes a transparent substrate having a first surface and a second surface, an EL layer and a transparent electrically conductive layer interposed between the EL layer and the second surface of the transparent substrate. The EL lamp further includes an insulating layer and an electrically conductive layer. In accordance with the present invention, the method further includes steps of providing a translucent layer having a first surface and a second surface, affixing the second surface of the translucent layer to the first surface of the transparent substrate and forming a surface configuration on the first surface of the translucent layer. In one embodiment, the step of forming includes forming either a coarse or a smooth textured finish on the first surface of the translucent layer.